iPhone as bluetooth keyboard for iPad

Please do not respond with links or information about iPhone apps requiring a helper app to control a Mac/PC.
Im looking for an app that will turn an iPhone/iPod Touch into a keyboard for iPad.
The closest thing Ive been able to find is External Keyboard. The dealbreaker with External Keyboard is that the iPad must also be running External Keyboard in order to accept input from the iPhone.
Looking forward to your tips and pointers.
2.93 GHz Quad-Core Xeon; dual 2.5 GHz G5; MBA 128GB SSD; iPhone 3G Mac OS X (10.5.8)